In an exam I have the following sentence that requires students to put the verb into the passive in the correct form.
It's freezing in here. _____________ the heating ____________? (turn off)
I believe it to be 'Has the heating been turned off?'
However, is 'Is the heating turned off?' or 'Was the heating turned off' acceptable?
Yup, it's a lousy question, as given the right context any of the three would be acceptable. But if the only context you have is 'It's an exam question' the answer they're looking for is 'Has...'.
I'd say the quality of the question would depend on how many answers they accept- it's possible that all three are OK, which makes it correct, though it is unclear what they are testing. This would be a dreadful multiple choice question.